drm/msm: Add pm_suspend/resume callbacks to msm_kms

Used by the dpu driver for custom suspend/resume.

Changes in v3:
- None
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
[seanpaul split this out of the megapatch]
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.c

@@ -903,6 +903,11 @@ static int msm_pm_suspend(struct device *dev)
 {
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct msm_drm_private *priv = ddev->dev_private;
+	struct msm_kms *kms = priv->kms;
+
+	/* TODO: Use atomic helper suspend/resume */
+	if (kms && kms->funcs && kms->funcs->pm_suspend)
+		return kms->funcs->pm_suspend(dev);
 
 	drm_kms_helper_poll_disable(ddev);
 
@@ -919,6 +924,11 @@ static int msm_pm_resume(struct device *dev)
 {
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct msm_drm_private *priv = ddev->dev_private;
+	struct msm_kms *kms = priv->kms;
+
+	/* TODO: Use atomic helper suspend/resume */
+	if (kms && kms->funcs && kms->funcs->pm_resume)
+		return kms->funcs->pm_resume(dev);
 
 	drm_atomic_helper_resume(ddev, priv->pm_state);
 	drm_kms_helper_poll_enable(ddev);

drivers/gpu/drm/msm/msm_kms.h

@@ -61,6 +61,9 @@ struct msm_kms_funcs {
 	void (*set_encoder_mode)(struct msm_kms *kms,
 				 struct drm_encoder *encoder,
 				 bool cmd_mode);
+	/* pm suspend/resume hooks */
+	int (*pm_suspend)(struct device *dev);
+	int (*pm_resume)(struct device *dev);
 	/* cleanup: */
 	void (*destroy)(struct msm_kms *kms);
 #ifdef CONFIG_DEBUG_FS